This invention relates to a corona discharge treatment apparatus used for activating a surface of an object to be treated to improve its surface property.
For example, automobile bumpers made of polyolefine material, etc., are subjected to corona discharge treatment for improvement their surface properties. As an apparatus for making this corona discharge treatment, there has been developed one that is equipped not only with a base electrode for coming in contact with an object but also with a discharge electrode for impressing a high voltage between it and the aforementioned base electrode, and which is adapted to activate a surface to be treated of the object by taking advantage of the corona discharge phenomenon that occurs when the high voltage is impressed between the aforementioned two electrodes, with the surface to be treated of the object and the aforementioned discharge electrode accommodated to each other.
To perform such a corona discharge treatment, a high voltage needs to be impressed between the base electrode and the discharge electrode. In order to conduct this, one of the electrodes must be linked to a high frequency and high voltage source, and the other electrode must be grounded. If the object has many surfaces to be treated, it is necessary, at every treatment of each surface to be treated, to vary a direction, etc., of the object or the electrode to be linked to the high frequency and high voltage source, thereby accommodating the surface to be treated of the object and the electrode to be linked to the high frequency and high voltage source to each other. In the aforementioned corona discharge treatment apparatus, this movement for accommodation has been provided by moving the electrode to be linked to the high frequency and high voltage source. For such a corona discharge treatment apparatus, an example appears in Japanese Patent Publication (examined) No. 60-46133. In the corona discharge treatment apparatus shown in the Patent Publication No. 60-46133, a base electrode is installed on a support and on this base electrode, an object is mounted; upward thereof, there is arranged an opposite electrode (discharge electrode) which has a flexible discharge device and is linked to the high frequency and high voltage source. A surface to be treated of the object and the discharge device are accommodated to each other by moving on a straight line or rotating the support together with the base electrode, or by moving up - down, swiveling or rotating the opposite electrode together with the discharge device, so that each surface to be treated of the object having many faces may be collectively and concentrically subjected to the discharge treatment. Further, in another corona discharge treatment apparatus which was developed separately from the corona discharge treatment apparatus shown in the Patent Publication No. 60-46133, an electrode to be linked to the high frequency and high voltage source is also designed to be vibrated for enhancing the effect of the corona discharge treatment. However, since such conventional corona discharge treatment apparatuses are designed to allow the electrode to be linked to the high frequency and high voltage source to be moved, accidents of an electric shock or a short-circuit often result from an unexpected contact of the electrode on an operator or installation, or troubles often result from spark or coming-apart of contacts.